+/* Copyright (c) 2013 Nicira, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License. */
+
+#include <config.h>
+#include "bfd.h"
+
+#include <arpa/inet.h>
+
+#include "csum.h"
+#include "dpif.h"
+#include "dynamic-string.h"
+#include "flow.h"
+#include "hash.h"
+#include "hmap.h"
+#include "list.h"
+#include "netlink.h"
+#include "odp-util.h"
+#include "ofpbuf.h"
+#include "openvswitch/types.h"
+#include "packets.h"
+#include "poll-loop.h"
+#include "random.h"
+#include "smap.h"
+#include "timeval.h"
+#include "unixctl.h"
+#include "util.h"
+#include "vlog.h"
+
+VLOG_DEFINE_THIS_MODULE(bfd);
+
+/* XXX Finish BFD.
+ *
+ * The goal of this module is to replace CFM with something both more flexible
+ * and standards compliant. In service of this goal, the following needs to be
+ * done.
+ *
+ * - Compliance
+ * * Implement Demand mode.
+ * * Go through the RFC line by line and verify we comply.
+ * * Test against a hardware implementation. Preferably a popular one.
+ * * Delete BFD packets with nw_ttl != 255 in the datapath to prevent DOS
+ * attacks.
+ *
+ * - Unit tests.
+ *
+ * - BFD show into ovs-bugtool.
+ *
+ * - Set TOS/PCP on inner BFD frame, and outer tunnel header when encapped.
+ *
+ * - CFM "check_tnl_key" option equivalent.
+ *
+ * - CFM "fault override" equivalent.
+ *
+ * - Sending BFD messages should be in its own thread/process.
+ *
+ * - Scale testing. How does it operate when there are large number of bfd
+ * sessions? Do we ever have random flaps? What's the CPU utilization?
+ *
+ * - Rely on data traffic for liveness by using BFD demand mode.
+ * If we're receiving traffic on a port, we can safely assume it's up (modulo
+ * unidrectional failures). BFD has a demand mode in which it can stay quiet
+ * unless it feels the need to check the status of the port. Using this, we
+ * can implement a strategy in which BFD only sends control messages on dark
+ * interfaces.
+ *
+ * - Depending on how one interprets the spec, it appears that a BFD session
+ * can never change bfd.LocalDiag to "No Diagnostic". We should verify that
+ * this is what hardware implementations actually do. Seems like "No
+ * Diagnostic" should be set once a BFD session state goes UP. */
+
+#define BFD_VERSION 1
+
+enum flags {
+ FLAG_MULTIPOINT = 1 << 0,
+ FLAG_DEMAND = 1 << 1,
+ FLAG_AUTH = 1 << 2,
+ FLAG_CTL = 1 << 3,
+ FLAG_FINAL = 1 << 4,
+ FLAG_POLL = 1 << 5
+};
+
+enum state {
+ STATE_ADMIN_DOWN = 0 << 6,
+ STATE_DOWN = 1 << 6,
+ STATE_INIT = 2 << 6,
+ STATE_UP = 3 << 6
+};
+
+enum diag {
+ DIAG_NONE = 0, /* No Diagnostic. */
+ DIAG_EXPIRED = 1, /* Control Detection Time Expired. */
+ DIAG_ECHO_FAILED = 2, /* Echo Function Failed. */
+ DIAG_RMT_DOWN = 3, /* Neighbor Signaled Session Down. */
+ DIAG_FWD_RESET = 4, /* Forwarding Plane Reset. */
+ DIAG_PATH_DOWN = 5, /* Path Down. */
+ DIAG_CPATH_DOWN = 6, /* Concatenated Path Down. */
+ DIAG_ADMIN_DOWN = 7, /* Administratively Down. */
+ DIAG_RCPATH_DOWN = 8 /* Reverse Concatenated Path Down. */
+};
+
+/* RFC 5880 Section 4.1
+ * 0 1 2 3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |Vers | Diag |Sta|P|F|C|A|D|M| Detect Mult | Length |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | My Discriminator |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | Your Discriminator |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | Desired Min TX Interval |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | Required Min RX Interval |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | Required Min Echo RX Interval |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
+struct msg {
+ uint8_t vers_diag; /* Version and diagnostic. */
+ uint8_t flags; /* 2bit State field followed by flags. */
+ uint8_t mult; /* Fault detection multiplier. */
+ uint8_t length; /* Length of this BFD message. */
+ ovs_be32 my_disc; /* My discriminator. */
+ ovs_be32 your_disc; /* Your discriminator. */
+ ovs_be32 min_tx; /* Desired minimum tx interval. */
+ ovs_be32 min_rx; /* Required minimum rx interval. */
+ ovs_be32 min_rx_echo; /* Required minimum echo rx interval. */
+};
+BUILD_ASSERT_DECL(BFD_PACKET_LEN == sizeof(struct msg));
+
+#define DIAG_MASK 0x1f
+#define VERS_SHIFT 5
+#define STATE_MASK 0xC0
+#define FLAGS_MASK 0x3f
+
+struct bfd {
+ struct hmap_node node; /* In 'all_bfds'. */
+ uint32_t disc; /* bfd.LocalDiscr. Key in 'all_bfds' hmap. */
+
+ char *name; /* Name used for logging. */
+
+ bool cpath_down; /* Concatenated Path Down. */
+ uint8_t mult; /* bfd.DetectMult. */
+
+ enum state state; /* bfd.SessionState. */
+ enum state rmt_state; /* bfd.RemoteSessionState. */
+
+ enum diag diag; /* bfd.LocalDiag. */
+ enum diag rmt_diag; /* Remote diagnostic. */
+
+ enum flags flags; /* Flags sent on messages. */
+ enum flags rmt_flags; /* Flags last received. */
+
+ uint32_t rmt_disc; /* bfd.RemoteDiscr. */
+
+ uint16_t udp_src; /* UDP source port. */
+
+ /* All timers in milliseconds. */
+ long long int rmt_min_rx; /* bfd.RemoteMinRxInterval. */
+ long long int rmt_min_tx; /* Remote minimum TX interval. */
+
+ long long int cfg_min_tx; /* Configured minimum TX rate. */
+ long long int cfg_min_rx; /* Configured required minimum RX rate. */
+ long long int poll_min_tx; /* Min TX negotating in a poll sequence. */
+ long long int poll_min_rx; /* Min RX negotating in a poll sequence. */
+ long long int min_tx; /* bfd.DesiredMinTxInterval. */
+ long long int min_rx; /* bfd.RequiredMinRxInterval. */
+
+ long long int last_tx; /* Last TX time. */
+ long long int next_tx; /* Next TX time. */
+ long long int detect_time; /* RFC 5880 6.8.4 Detection time. */
+};
+
+static bool bfd_in_poll(const struct bfd *);
+static void bfd_poll(struct bfd *bfd);
+static const char *bfd_diag_str(enum diag);
+static const char *bfd_state_str(enum state);
+static long long int bfd_min_tx(const struct bfd *);
+static long long int bfd_tx_interval(const struct bfd *);
+static long long int bfd_rx_interval(const struct bfd *);
+static void bfd_set_next_tx(struct bfd *);
+static void bfd_set_state(struct bfd *, enum state, enum diag);
+static uint32_t generate_discriminator(void);
+static void bfd_put_details(struct ds *, const struct bfd *);
+static void bfd_unixctl_show(struct unixctl_conn *, int argc,
+ const char *argv[], void *aux OVS_UNUSED);
+static void log_msg(enum vlog_level, const struct msg *, const char *message,
+ const struct bfd *);
+
+static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(20, 20);
+static struct hmap all_bfds = HMAP_INITIALIZER(&all_bfds);
+
+/* Returns true if the interface on which 'bfd' is running may be used to
+ * forward traffic according to the BFD session state. */
+bool
+bfd_forwarding(const struct bfd *bfd)
+{
+ return bfd->state == STATE_UP
+ && bfd->rmt_diag != DIAG_PATH_DOWN
+ && bfd->rmt_diag != DIAG_CPATH_DOWN
+ && bfd->rmt_diag != DIAG_RCPATH_DOWN;
+}
+
+/* Returns a 'smap' of key value pairs representing the status of 'bfd'
+ * intended for the OVS database. */
+void
+bfd_get_status(const struct bfd *bfd, struct smap *smap)
+{
+ smap_add(smap, "forwarding", bfd_forwarding(bfd) ? "true" : "false");
+ smap_add(smap, "state", bfd_state_str(bfd->state));
+ smap_add(smap, "diagnostic", bfd_diag_str(bfd->diag));
+
+ if (bfd->state != STATE_DOWN) {
+ smap_add(smap, "remote_state", bfd_state_str(bfd->rmt_state));
+ smap_add(smap, "remote_diagnostic", bfd_diag_str(bfd->rmt_diag));
+ }
+}
+
+/* Initializes, destroys, or reconfigures the BFD session 'bfd' (named 'name'),
+ * according to the database configuration contained in 'cfg'. Takes ownership
+ * of 'bfd', which may be NULL. Returns a BFD object which may be used as a
+ * handle for the session, or NULL if BFD is not enabled according to 'cfg'. */
+struct bfd *
+bfd_configure(struct bfd *bfd, const char *name,
+ const struct smap *cfg)
+{
+ static uint16_t udp_src = 0;
+ static bool init = false;
+
+ long long int min_tx, min_rx;
+ bool cpath_down;
+
+ if (!init) {
+ unixctl_command_register("bfd/show", "[interface]", 0, 1,
+ bfd_unixctl_show, NULL);
+ init = true;
+ }
+
+ if (!smap_get_bool(cfg, "enable", false)) {
+ if (bfd) {
+ hmap_remove(&all_bfds, &bfd->node);
+ free(bfd->name);
+ free(bfd);
+ }
+ return NULL;
+ }
+
+ if (!bfd) {
+ bfd = xzalloc(sizeof *bfd);
+ bfd->name = xstrdup(name);
+ bfd->disc = generate_discriminator();
+ hmap_insert(&all_bfds, &bfd->node, bfd->disc);
+
+ bfd->diag = DIAG_NONE;
+ bfd->min_tx = 1000;
+ bfd->mult = 3;
+
+ /* RFC 5881 section 4
+ * The source port MUST be in the range 49152 through 65535. The same
+ * UDP source port number MUST be used for all BFD Control packets
+ * associated with a particular session. The source port number SHOULD
+ * be unique among all BFD sessions on the system. */
+ bfd->udp_src = (udp_src++ % 16384) + 49152;
+
+ bfd_set_state(bfd, STATE_DOWN, DIAG_NONE);
+ }
+
+ min_tx = smap_get_int(cfg, "min_tx", 100);
+ min_tx = MAX(min_tx, 100);
+ if (bfd->cfg_min_tx != min_tx) {
+ bfd->cfg_min_tx = min_tx;
+ if (bfd->state != STATE_UP
+ || (!bfd_in_poll(bfd) && bfd->cfg_min_tx < bfd->min_tx)) {
+ bfd->min_tx = bfd->cfg_min_tx;
+ }
+ bfd_poll(bfd);
+ }
+
+ min_rx = smap_get_int(cfg, "min_rx", 1000);
+ min_rx = MAX(min_rx, 100);
+ if (bfd->cfg_min_rx != min_rx) {
+ bfd->cfg_min_rx = min_rx;
+ if (bfd->state != STATE_UP
+ || (!bfd_in_poll(bfd) && bfd->cfg_min_rx > bfd->min_rx)) {
+ bfd->min_rx = bfd->cfg_min_rx;
+ }
+ bfd_poll(bfd);
+ }
+
+ cpath_down = smap_get_bool(cfg, "cpath_down", false);
+ if (bfd->cpath_down != cpath_down) {
+ bfd->cpath_down = cpath_down;
+ if (bfd->diag == DIAG_NONE || bfd->diag == DIAG_CPATH_DOWN) {
+ bfd_set_state(bfd, bfd->state, DIAG_NONE);
+ }
+ bfd_poll(bfd);
+ }
+ return bfd;
+}
+
+void
+bfd_wait(const struct bfd *bfd)
+{
+ if (bfd->flags & FLAG_FINAL) {
+ poll_immediate_wake();
+ }
+
+ poll_timer_wait_until(bfd->next_tx);
+ if (bfd->state > STATE_DOWN) {
+ poll_timer_wait_until(bfd->detect_time);
+ }
+}
+
+void
+bfd_run(struct bfd *bfd)
+{
+ if (bfd->state > STATE_DOWN && time_msec() >= bfd->detect_time) {
+ bfd_set_state(bfd, STATE_DOWN, DIAG_EXPIRED);
+ }
+
+ if (bfd->min_tx != bfd->cfg_min_tx || bfd->min_rx != bfd->cfg_min_rx) {
+ bfd_poll(bfd);
+ }
+}
+
+bool
+bfd_should_send_packet(const struct bfd *bfd)
+{
+ return bfd->flags & FLAG_FINAL || time_msec() >= bfd->next_tx;
+}
+
+void
+bfd_put_packet(struct bfd *bfd, struct ofpbuf *p,
+ uint8_t eth_src[ETH_ADDR_LEN])
+{
+ long long int min_tx, min_rx;
+ struct udp_header *udp;
+ struct eth_header *eth;
+ struct ip_header *ip;
+ struct msg *msg;
+
+ if (bfd->next_tx) {
+ long long int delay = time_msec() - bfd->next_tx;
+ long long int interval = bfd_tx_interval(bfd);
+ if (delay > interval * 3 / 2) {
+ VLOG_WARN("%s: long delay of %lldms (expected %lldms) sending BFD"
+ " control message", bfd->name, delay, interval);
+ }
+ }
+
+ /* RFC 5880 Section 6.5
+ * A BFD Control packet MUST NOT have both the Poll (P) and Final (F) bits
+ * set. */
+ ovs_assert(!(bfd->flags & FLAG_POLL) || !(bfd->flags & FLAG_FINAL));
+
+ ofpbuf_reserve(p, 2); /* Properly align after the ethernet header. */
+ eth = ofpbuf_put_uninit(p, sizeof *eth);
+ memcpy(eth->eth_dst, eth_addr_broadcast, ETH_ADDR_LEN);
+ memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
+ eth->eth_type = htons(ETH_TYPE_IP);
+
+ ip = ofpbuf_put_zeros(p, sizeof *ip);
+ ip->ip_ihl_ver = IP_IHL_VER(5, 4);
+ ip->ip_tot_len = htons(sizeof *ip + sizeof *udp + sizeof *msg);
+ ip->ip_ttl = 255;
+ ip->ip_proto = IPPROTO_UDP;
+ ip->ip_src = htonl(0xA9FE0100); /* 169.254.1.0 Link Local. */
+ ip->ip_dst = htonl(0xA9FE0101); /* 169.254.1.1 Link Local. */
+ ip->ip_csum = csum(ip, sizeof *ip);
+
+ udp = ofpbuf_put_zeros(p, sizeof *udp);
+ udp->udp_src = htons(bfd->udp_src);
+ udp->udp_dst = htons(BFD_DEST_PORT);
+ udp->udp_len = htons(sizeof *udp + sizeof *msg);
+
+ msg = ofpbuf_put_uninit(p, sizeof *msg);
+ msg->vers_diag = (BFD_VERSION << 5) | bfd->diag;
+ msg->flags = (bfd->state & STATE_MASK) | bfd->flags;
+
+ msg->mult = bfd->mult;
+ msg->length = BFD_PACKET_LEN;
+ msg->my_disc = htonl(bfd->disc);
+ msg->your_disc = htonl(bfd->rmt_disc);
+ msg->min_rx_echo = htonl(0);
+
+ if (bfd_in_poll(bfd)) {
+ min_tx = bfd->poll_min_tx;
+ min_rx = bfd->poll_min_rx;
+ } else {
+ min_tx = bfd_min_tx(bfd);
+ min_rx = bfd->min_rx;
+ }
+
+ msg->min_tx = htonl(min_tx * 1000);
+ msg->min_rx = htonl(min_rx * 1000);
+
+ bfd->flags &= ~FLAG_FINAL;
+
+ log_msg(VLL_DBG, msg, "Sending BFD Message", bfd);
+
+ bfd->last_tx = time_msec();
+ bfd_set_next_tx(bfd);
+}
+
+bool
+bfd_should_process_flow(const struct flow *flow)
+{
+ return (flow->dl_type == htons(ETH_TYPE_IP)
+ && flow->nw_proto == IPPROTO_UDP
+ && flow->tp_dst == htons(3784));
+}
+
+void
+bfd_process_packet(struct bfd *bfd, const struct flow *flow,
+ const struct ofpbuf *p)
+{
+ uint32_t rmt_min_rx, pkt_your_disc;
+ enum state rmt_state;
+ enum flags flags;
+ uint8_t version;
+ struct msg *msg;
+
+ /* This function is designed to follow section RFC 5880 6.8.6 closely. */
+
+ if (flow->nw_ttl != 255) {
+ /* XXX Should drop in the kernel to prevent DOS. */
+ return;
+ }
+
+ msg = ofpbuf_at(p, (uint8_t *)p->l7 - (uint8_t *)p->data, BFD_PACKET_LEN);
+ if (!msg) {
+ VLOG_INFO_RL(&rl, "%s: Received unparseable BFD control message.",
+ bfd->name);
+ return;
+ }
+
+ /* RFC 5880 Section 6.8.6
+ * If the Length field is greater than the payload of the encapsulating
+ * protocol, the packet MUST be discarded.
+ *
+ * Note that we make this check implicity. Above we use ofpbuf_at() to
+ * ensure that there are at least BFD_PACKET_LEN bytes in the payload of
+ * the encapsulating protocol. Below we require msg->length to be exactly
+ * BFD_PACKET_LEN bytes. */
+
+ flags = msg->flags & FLAGS_MASK;
+ rmt_state = msg->flags & STATE_MASK;
+ version = msg->vers_diag >> VERS_SHIFT;
+
+ log_msg(VLL_DBG, msg, "Received BFD control message", bfd);
+
+ if (version != BFD_VERSION) {
+ log_msg(VLL_WARN, msg, "Incorrect version", bfd);
+ return;
+ }
+
+ /* Technically this should happen after the length check. We don't support
+ * authentication however, so it's simpler to do the check first. */
+ if (flags & FLAG_AUTH) {
+ log_msg(VLL_WARN, msg, "Authenticated control message with"
+ " authentication disabled", bfd);
+ return;
+ }
+
+ if (msg->length != BFD_PACKET_LEN) {
+ log_msg(VLL_WARN, msg, "Unexpected length", bfd);
+ if (msg->length < BFD_PACKET_LEN) {
+ return;
+ }
+ }
+
+ if (!msg->mult) {
+ log_msg(VLL_WARN, msg, "Zero multiplier", bfd);
+ return;
+ }
+
+ if (flags & FLAG_MULTIPOINT) {
+ log_msg(VLL_WARN, msg, "Unsupported multipoint flag", bfd);
+ return;
+ }
+
+ if (!msg->my_disc) {
+ log_msg(VLL_WARN, msg, "NULL my_disc", bfd);
+ return;
+ }
+
+ pkt_your_disc = ntohl(msg->your_disc);
+ if (pkt_your_disc) {
+ /* Technically, we should use the your discriminator field to figure
+ * out which 'struct bfd' this packet is destined towards. That way a
+ * bfd session could migrate from one interface to another
+ * transparently. This doesn't fit in with the OVS structure very
+ * well, so in this respect, we are not compliant. */
+ if (pkt_your_disc != bfd->disc) {
+ log_msg(VLL_WARN, msg, "Incorrect your_disc", bfd);
+ return;
+ }
+ } else if (rmt_state > STATE_DOWN) {
+ log_msg(VLL_WARN, msg, "Null your_disc", bfd);
+ return;
+ }
+
+ bfd->rmt_disc = ntohl(msg->my_disc);
+ bfd->rmt_state = rmt_state;
+ bfd->rmt_flags = flags;
+ bfd->rmt_diag = msg->vers_diag & DIAG_MASK;
+
+ if (flags & FLAG_FINAL && bfd_in_poll(bfd)) {
+ bfd->min_tx = bfd->poll_min_tx;
+ bfd->min_rx = bfd->poll_min_rx;
+ bfd->flags &= ~FLAG_POLL;
+ log_msg(VLL_INFO, msg, "Poll sequence terminated", bfd);
+ }
+
+ if (flags & FLAG_POLL) {
+ /* RFC 5880 Section 6.5
+ * When the other system receives a Poll, it immediately transmits a
+ * BFD Control packet with the Final (F) bit set, independent of any
+ * periodic BFD Control packets it may be sending
+ * (see section 6.8.7). */
+ bfd->flags &= ~FLAG_POLL;
+ bfd->flags |= FLAG_FINAL;
+ }
+
+ rmt_min_rx = MAX(ntohl(msg->min_rx) / 1000, 1);
+ if (bfd->rmt_min_rx != rmt_min_rx) {
+ bfd->rmt_min_rx = rmt_min_rx;
+ bfd_set_next_tx(bfd);
+ log_msg(VLL_INFO, msg, "New remote min_rx", bfd);
+ }
+
+ bfd->rmt_min_tx = MAX(ntohl(msg->min_tx) / 1000, 1);
+ bfd->detect_time = bfd_rx_interval(bfd) * bfd->mult + time_msec();
+
+ if (bfd->state == STATE_ADMIN_DOWN) {
+ VLOG_DBG_RL(&rl, "Administratively down, dropping control message.");
+ return;
+ }
+
+ if (rmt_state == STATE_ADMIN_DOWN) {
+ if (bfd->state != STATE_DOWN) {
+ bfd_set_state(bfd, STATE_DOWN, DIAG_RMT_DOWN);
+ }
+ } else {
+ switch (bfd->state) {
+ case STATE_DOWN:
+ if (rmt_state == STATE_DOWN) {
+ bfd_set_state(bfd, STATE_INIT, bfd->diag);
+ } else if (rmt_state == STATE_INIT) {
+ bfd_set_state(bfd, STATE_UP, bfd->diag);
+ }
+ break;
+ case STATE_INIT:
+ if (rmt_state > STATE_DOWN) {
+ bfd_set_state(bfd, STATE_UP, bfd->diag);
+ }
+ break;
+ case STATE_UP:
+ if (rmt_state <= STATE_DOWN) {
+ bfd_set_state(bfd, STATE_DOWN, DIAG_RMT_DOWN);
+ log_msg(VLL_INFO, msg, "Remote signaled STATE_DOWN", bfd);
+ }
+ break;
+ case STATE_ADMIN_DOWN:
+ default:
+ NOT_REACHED();
+ }
+ }
+ /* XXX: RFC 5880 Section 6.8.6 Demand mode related calculations here. */
+}
+\f
+/* Helpers. */
+static bool
+bfd_in_poll(const struct bfd *bfd)
+{
+ return (bfd->flags & FLAG_POLL) != 0;
+}
+
+static void
+bfd_poll(struct bfd *bfd)
+{
+ if (bfd->state > STATE_DOWN && !bfd_in_poll(bfd)
+ && !(bfd->flags & FLAG_FINAL)) {
+ bfd->poll_min_tx = bfd->cfg_min_tx;
+ bfd->poll_min_rx = bfd->cfg_min_rx;
+ bfd->flags |= FLAG_POLL;
+ bfd->next_tx = 0;
+ VLOG_INFO_RL(&rl, "%s: Initiating poll sequence", bfd->name);
+ }
+}
+
+static long long int
+bfd_min_tx(const struct bfd *bfd)
+{
+ /* RFC 5880 Section 6.8.3
+ * When bfd.SessionState is not Up, the system MUST set
+ * bfd.DesiredMinTxInterval to a value of not less than one second
+ * (1,000,000 microseconds). This is intended to ensure that the
+ * bandwidth consumed by BFD sessions that are not Up is negligible,
+ * particularly in the case where a neighbor may not be running BFD. */
+ return (bfd->state == STATE_UP ? bfd->min_tx : MAX(bfd->min_tx, 1000));
+}
+
+static long long int
+bfd_tx_interval(const struct bfd *bfd)
+{
+ long long int interval = bfd_min_tx(bfd);
+ return MAX(interval, bfd->rmt_min_rx);
+}
+
+static long long int
+bfd_rx_interval(const struct bfd *bfd)
+{
+ return MAX(bfd->min_rx, bfd->rmt_min_tx);
+}
+
+static void
+bfd_set_next_tx(struct bfd *bfd)
+{
+ long long int interval = bfd_tx_interval(bfd);
+ interval -= interval * random_range(26) / 100;
+ bfd->next_tx = bfd->last_tx + interval;
+}
+
+static const char *
+bfd_flag_str(enum flags flags)
+{
+ struct ds ds = DS_EMPTY_INITIALIZER;
+ static char flag_str[128];
+
+ if (!flags) {
+ return "none";
+ }
+
+ if (flags & FLAG_MULTIPOINT) {
+ ds_put_cstr(&ds, "multipoint ");
+ }
+
+ if (flags & FLAG_DEMAND) {
+ ds_put_cstr(&ds, "demand ");
+ }
+
+ if (flags & FLAG_AUTH) {
+ ds_put_cstr(&ds, "auth ");
+ }
+
+ if (flags & FLAG_CTL) {
+ ds_put_cstr(&ds, "ctl ");
+ }
+
+ if (flags & FLAG_FINAL) {
+ ds_put_cstr(&ds, "final ");
+ }
+
+ if (flags & FLAG_POLL) {
+ ds_put_cstr(&ds, "poll ");
+ }
+
+ ovs_strlcpy(flag_str, ds_cstr(&ds), sizeof flag_str);
+ ds_destroy(&ds);
+ return flag_str;
+}
+
+static const char *
+bfd_state_str(enum state state)
+{
+ switch (state) {
+ case STATE_ADMIN_DOWN: return "admin_down";
+ case STATE_DOWN: return "down";
+ case STATE_INIT: return "init";
+ case STATE_UP: return "up";
+ default: return "invalid";
+ }
+}
+
+static const char *
+bfd_diag_str(enum diag diag) {
+ switch (diag) {
+ case DIAG_NONE: return "No Diagnostic";
+ case DIAG_EXPIRED: return "Control Detection Time Expired";
+ case DIAG_ECHO_FAILED: return "Echo Function Failed";
+ case DIAG_RMT_DOWN: return "Neighbor Signaled Session Down";
+ case DIAG_FWD_RESET: return "Forwarding Plane Reset";
+ case DIAG_PATH_DOWN: return "Path Down";
+ case DIAG_CPATH_DOWN: return "Concatenated Path Down";
+ case DIAG_ADMIN_DOWN: return "Administratively Down";
+ case DIAG_RCPATH_DOWN: return "Reverse Concatenated Path Down";
+ default: return "Invalid Diagnostic";
+ }
+};
+
+static void
+log_msg(enum vlog_level level, const struct msg *p, const char *message,
+ const struct bfd *bfd)
+{
+ struct ds ds = DS_EMPTY_INITIALIZER;
+
+ if (vlog_should_drop(THIS_MODULE, level, &rl)) {
+ return;
+ }
+
+ ds_put_format(&ds,
+ "%s: %s."
+ "\n\tvers:%"PRIu8" diag:\"%s\" state:%s mult:%"PRIu8
+ " length:%"PRIu8
+ "\n\tflags: %s"
+ "\n\tmy_disc:0x%"PRIx32" your_disc:0x%"PRIx32
+ "\n\tmin_tx:%"PRIu32"us (%"PRIu32"ms)"
+ "\n\tmin_rx:%"PRIu32"us (%"PRIu32"ms)"
+ "\n\tmin_rx_echo:%"PRIu32"us (%"PRIu32"ms)",
+ bfd->name, message, p->vers_diag >> VERS_SHIFT,
+ bfd_diag_str(p->vers_diag & DIAG_MASK),
+ bfd_state_str(p->flags & STATE_MASK),
+ p->mult, p->length, bfd_flag_str(p->flags & FLAGS_MASK),
+ ntohl(p->my_disc), ntohl(p->your_disc),
+ ntohl(p->min_tx), ntohl(p->min_tx) / 1000,
+ ntohl(p->min_rx), ntohl(p->min_rx) / 1000,
+ ntohl(p->min_rx_echo), ntohl(p->min_rx_echo) / 1000);
+ bfd_put_details(&ds, bfd);
+ VLOG(level, "%s", ds_cstr(&ds));
+ ds_destroy(&ds);
+}
+
+static void
+bfd_set_state(struct bfd *bfd, enum state state, enum diag diag)
+{
+ if (diag == DIAG_NONE && bfd->cpath_down) {
+ diag = DIAG_CPATH_DOWN;
+ }
+
+ if (bfd->state != state || bfd->diag != diag) {
+ if (!VLOG_DROP_INFO(&rl)) {
+ struct ds ds = DS_EMPTY_INITIALIZER;
+
+ ds_put_format(&ds, "%s: BFD state change: %s->%s"
+ " \"%s\"->\"%s\".\n",
+ bfd->name, bfd_state_str(bfd->state),
+ bfd_state_str(state), bfd_diag_str(bfd->diag),
+ bfd_diag_str(diag));
+ bfd_put_details(&ds, bfd);
+ VLOG_INFO("%s", ds_cstr(&ds));
+ ds_destroy(&ds);
+ }
+
+ bfd->state = state;
+ bfd->diag = diag;
+
+ if (bfd->state <= STATE_DOWN) {
+ bfd->rmt_state = STATE_DOWN;
+ bfd->rmt_diag = DIAG_NONE;
+ bfd->rmt_min_rx = 1;
+ bfd->rmt_flags = 0;
+ bfd->rmt_disc = 0;
+ bfd->rmt_min_tx = 0;
+ }
+ }
+}
+
+static uint32_t
+generate_discriminator(void)
+{
+ uint32_t disc = 0;
+
+ /* RFC 5880 Section 6.8.1
+ * It SHOULD be set to a random (but still unique) value to improve
+ * security. The value is otherwise outside the scope of this
+ * specification. */
+
+ while (!disc) {
+ struct bfd *bfd;
+
+ /* 'disc' is by defnition random, so there's no reason to waste time
+ * hashing it. */
+ disc = random_uint32();
+ HMAP_FOR_EACH_IN_BUCKET (bfd, node, disc, &all_bfds) {
+ if (bfd->disc == disc) {
+ disc = 0;
+ break;
+ }
+ }
+ }
+
+ return disc;
+}
+
+static struct bfd *
+bfd_find_by_name(const char *name)
+{
+ struct bfd *bfd;
+
+ HMAP_FOR_EACH (bfd, node, &all_bfds) {
+ if (!strcmp(bfd->name, name)) {
+ return bfd;
+ }
+ }
+ return NULL;
+}
+
+static void
+bfd_put_details(struct ds *ds, const struct bfd *bfd)
+{
+ ds_put_format(ds, "\tForwarding: %s\n",
+ bfd_forwarding(bfd) ? "true" : "false");
+ ds_put_format(ds, "\tDetect Multiplier: %d\n", bfd->mult);
+ ds_put_format(ds, "\tConcatenated Path Down: %s\n",
+ bfd->cpath_down ? "true" : "false");
+ ds_put_format(ds, "\tTX Interval: Approx %lldms\n", bfd_tx_interval(bfd));
+ ds_put_format(ds, "\tRX Interval: Approx %lldms\n", bfd_rx_interval(bfd));
+ ds_put_format(ds, "\tDetect Time: now %+lldms\n",
+ time_msec() - bfd->detect_time);
+ ds_put_format(ds, "\tNext TX Time: now %+lldms\n",
+ time_msec() - bfd->next_tx);
+ ds_put_format(ds, "\tLast TX Time: now %+lldms\n",
+ time_msec() - bfd->last_tx);
+
+ ds_put_cstr(ds, "\n");
+
+ ds_put_format(ds, "\tLocal Flags: %s\n", bfd_flag_str(bfd->flags));
+ ds_put_format(ds, "\tLocal Session State: %s\n",
+ bfd_state_str(bfd->state));
+ ds_put_format(ds, "\tLocal Diagnostic: %s\n", bfd_diag_str(bfd->diag));
+ ds_put_format(ds, "\tLocal Discriminator: 0x%"PRIx32"\n", bfd->disc);
+ ds_put_format(ds, "\tLocal Minimum TX Interval: %lldms\n",
+ bfd_min_tx(bfd));
+ ds_put_format(ds, "\tLocal Minimum RX Interval: %lldms\n", bfd->min_rx);
+
+ ds_put_cstr(ds, "\n");
+
+ ds_put_format(ds, "\tRemote Flags: %s\n", bfd_flag_str(bfd->rmt_flags));
+ ds_put_format(ds, "\tRemote Session State: %s\n",
+ bfd_state_str(bfd->rmt_state));
+ ds_put_format(ds, "\tRemote Diagnostic: %s\n",
+ bfd_diag_str(bfd->rmt_diag));
+ ds_put_format(ds, "\tRemote Discriminator: 0x%"PRIx32"\n", bfd->rmt_disc);
+ ds_put_format(ds, "\tRemote Minimum TX Interval: %lldms\n",
+ bfd->rmt_min_tx);
+ ds_put_format(ds, "\tRemote Minimum RX Interval: %lldms\n",
+ bfd->rmt_min_rx);
+}
+
+static void
+bfd_unixctl_show(struct unixctl_conn *conn, int argc, const char *argv[],
+ void *aux OVS_UNUSED)
+{
+ struct ds ds = DS_EMPTY_INITIALIZER;
+ struct bfd *bfd;
+
+ if (argc > 1) {
+ bfd = bfd_find_by_name(argv[1]);
+ if (!bfd) {
+ unixctl_command_reply_error(conn, "no such bfd object");
+ return;
+ }
+ bfd_put_details(&ds, bfd);
+ } else {
+ HMAP_FOR_EACH (bfd, node, &all_bfds) {
+ ds_put_format(&ds, "---- %s ----\n", bfd->name);
+ bfd_put_details(&ds, bfd);
+ }
+ }
+ unixctl_command_reply(conn, ds_cstr(&ds));
+ ds_destroy(&ds);
+}